In the past, there has been known a liquid crystal projector which combines three colored lights of red light, green light, and blue light with each other to thereby perform projection. In such a projector, a variation in, for example, accuracy of positioning of the optical system occurs in some cases. Further, if the variation occurs, color shift in the image projected on a screen occurs in some cases due to the displacement between the colored lights. There has been proposed a projector provided with a registration adjustment function for electrically correcting the color shift in order for reducing such color shift (e.g., Japanese Patent Publication No. 8-201937).
Incidentally, projectors are utilized in a variety of places such as companies, event sites, schools, or homes. As an installation posture of the projector in such places, there can be cited a posture for being mounted on the desk or the like to perform projection on a screen, a posture in which the projector is fixedly mounted upside down by being suspended from an overhead location such as a ceiling to perform projection, a posture in which the projector is installed behind the screen to perform projection, and so on. For example, since the image projected in the ceiling mount posture is displayed in an orientation (an orientation rotated 180°) flipped vertically and horizontally with respect to the case of projection performed in the normal posture, the user sets an image conversion function for flipping the projection image provided to the projector to thereby flip the orientation of the image projected from the projector to the orientation corresponding to the installation condition (posture).
Here, even in the case in which such an image conversion function is performed, the direction of the color shift due to the displacement between the colored lights described above does not change from before the image conversion is performed because the color shift depends on the hardware (the optical mechanism). Therefore, there arises a problem that when the user performs the registration adjustment, the correction direction (the adjustment direction) on the registration adjustment screen and the actual correction direction become different to thereby degrade the operability in performing the registration adjustment.